No, they are magic: arbitrary hardware designs run without the cost of chip fabrication. Two non-profit FPGA's, one for performance at 28nm & one for embedded at 28SLPnm, would totally address the custom hardware and subversion problem given we could just keep checking on that one. The PPC cores and soon Intel Xeons already show what a good CPU plus FPGA accleration w/ local memory can do for applications.

Yeah, buddy, they're like magic hardware. Even if they aren't ASIC-competitive for the best ASIC's. Still magic with a market share and diverse applications that shows it. :)

I thought that is clear? Apparently not...

FPGA's are cheap and good enough for prototyping; once one has a working VHDL / Verilog code, it's tapeout time.

Security wise, a FPGA is superior to consumer level x86 processors. How do you backdoor a FPGA?

In more ways than you'd know. They're already pre-backdoored like almost all other chips for debugging purposes in what's called Design for Test or scan chains or scan probes or something. Much hardware hacking involves getting to those suckers to see what chip is doing.

Now, for remote attacks, you can embed RF circuitry in them that listens to any of that. You can embed circuits that receive incoming command, then dump its SRAM contents. You might modify the I/O circuitry to recognize a trapdoor command that runs incoming data as privileged instructions. You can put a microcontroller in there connected to PCI to do the same for host PC attacks. I know, that would be first option but I was having too much fun with RTL and transistor level. :)